Abstract: An optical integrated circuit wherein the waveguide network is constructed of a passive waveguide and a functional material is used on the functional portions, an optical circuit device which uses transparent electrodes, an optical switch which uses transparent electrodes and a functional portion made of a non-linear optical material, a matrix optical switch which converts inputted and outputted light at an electrical/optical converter element, and an optical integrated circuit or optical circuit device prepared by selective vapor growth of a functional material on desired regions, as well as an organic film growth process by which an organic film is selectively grown on recess walls and an organic film formation process whereby organic CVD or MLD is performed using a chamber divided into multiple regions.

Abstract: The present invention relates to a new polyesterimide of the type containing ester repeat functional groups E=--CO--O--, imide repeat functional groups I: ##STR1## and at least one chromophore, characterized in that it contains a quantity of recurrent amide functional groups capable of ring closure to imides which is smaller than or equal to 5 mol % relative to the sum of the imide functional groups and of the amide functional groups capable of ring closure to imides, which are present, and in that the polymerization functional groups consist essentially of E functional groups.This polyesterimide is preferably free from amide functional groups capable of ring closure to imides.One of the processes for obtaining this polyesterimide constitutes another subject-matter of the invention.Such a polymer is advantageously capable of behaving like a material that is transparent and/or active in nonlinear optics.

Abstract: In accordance with the invention, a tunable fiber grating comprises a fiber grating secured to a magnetostrictive body so that magnetostrictive strain will be transmitted to the grating. An electromagnet is disposed adjacent the magnetostrictive body for applying a magnetic field along the body. Control of the current applied to the electromagnet permits control of the strain transmitted to the fiber grating, and thus control of the grating spacing and reflection frequency. In a preferred embodiment the magnetostrictive body is cylinder bonded along the grating. In alternative arrangements, the magnetostrictive effect can be mechanically amplified. An add/drop multiplexer employing the tunable gratings is described.

Abstract: Even when manufacturing of a waveguide is fluctuated and an optical parameter is fluctuated or a wavelength of emitted light is fluctuated, a phase difference between two intrinsic modes can be compensated (positive integral multiple of .pi.). Thus, it is possible to prevent a reproduced signal from being deteriorated by elliptically polarized light. A magneto-optical reproducing pickup includes an optical waveguide (4) for guiding light reflected on a magneto-optical recording medium to a differential photo-detecting unit (9) side and phase compensating circuitry for compensating a phase difference between light components of a TE mode an a TM mode included in reflected light.

Abstract: An optical deflecting device of optical waveguide type comprising: a conductive or semi-conductive monocrystalline substrate, or a monocrystalline substrate having a conductive or semi-conductive, epitaxial or oriented film provided on the surface thereof; an optical waveguide comprising an epitaxial or oriented ferroelectric film provided on the surface of the monocrystalline substrate; and an upper electrode disposed on top of the optical waveguide. In the optical deflecting device, the conductive or semi-conductive monocrystalline substrate, or the conductive or semi-conductive, epitaxial or oriented film provided on the monocrystalline substrate acts as a lower electrode. The laser beam introduced into the optical waveguide is deflected by applying a voltage between the upper electrode and the lower electrode.

Abstract: Color image generation systems are disclosed for the reproduction of real or virtual, two-dimenional or three-dimensional, color, or monochrome images and their applications, in particular for television or video applications, and printing applications. Integrated-optical structures are used on a mount, in particular a substrate. An image is generated by deflecting color light beams generated into a viewing space, which deflection is effected in synchronism with color setting and intensity- or amplitude modulation of the light. All electronic and optical assemblies for color image generation may be integrated on a mount either monolithically or in hybrid fashion. The color generation system may be implemented as an encased module.

Abstract: The short optical pulse generator is provided with a semiconductor laser which oscillates continuously at a single wavelength, a semiconductor electro-absorption type optical modulator which performs the intensity modulation of the output light from the laser, and a sinusoidal voltage generator and a DC voltage generator for driving the electro-absorption type optical modulator. A DC voltage is applied to the electro-absorption type optical modulator so that the output light from the laser is sufficiently extinguished. By applying a sinusoidal voltage to the optical modulator, short optical pulses are generated.

Abstract: An electromagnetic wave-to-optical signal converting and modulating device includes: a substrate presenting the electro-optical effect; at least a pair of optical waveguide paths which are formed on the substrate and arranged in parallel to each other and are joined at their ends; electrodes which are formed along the optical waveguide paths and have the antenna function for detecting electric field signals around the external space; a light supplying means with an optical fiber cable for supplying light to the optical waveguide paths; and an optical detector with a light signal receiver for detecting and processing the light emitted from the optical waveguide paths. This device directly modulates the light which is passing through the waveguide paths with an external space electric field signal carrying information.

Abstract: In an optical transmitter, an input optical fiber delivers an optical signal to a fiber coupling modulator whose reflective surface is transformable in response to the data to be transmitted. In a first state of the modulator corresponding to a first data value, the reflective surface is flat and smooth. The optical signal, which may be a continuous-wave light, is reflected from the surface and efficiently coupled to an output fiber. In a second state of the modulator corresponding to a second data value, the reflective surface is controllably deformed to cause an aberration in reflecting the optical signal. As a result, a much reduced amount of light energy is coupled to the output fiber.

Abstract: A semiconductor laser chip according to the present invention comprises: a p-type InP substrate; an InGaAsP active layer (optical waveguide) formed on said substrate; a p-n-p InP block layer formed on said substrate; a contact layer formed thereupon; an insulating film formed on said contact layer; a front surface electrode formed on said insulating film; a pair of alignment marks formed at the same time of the optical waveguide; and a back surface electrode formed on said substrate. The alignment marks are formed from the same material, i.e., the same crystal as said optical waveguide. Accordingly, it is possible to improve precision of the relative position between said optical waveguide and said alignment marks.

Abstract: A resonantly enhanced external electro-optic modulator reduces required drive power. The modulator has a coupling structure that efficiently couples power from a feed line into the resonator and eliminates the need for a terminal impedance. The modulator can be driven by a RF signal that is designed to suppress Stimulated Brillouin Scattering (SBS) in a long haul, high power fiber optic link, such as that used to transmit analog CATV signals. The modulator can also be used to depolarize an optical signal. A ring resonator includes a portion located outside the active area of the modulator in order to provide a space-efficient structure. The ring resonator can include one or more coaxial cable portions that are tuned to provide resonance at one or more frequencies that are matched to the input RF drive signal.

Abstract: An improved waveguide polymer electro-optic modulator/switch which is operated in a single mode and has an improved device characteristic compared to the optimized modulator/switch and is capable of enhancing a coupling efficiency with an optical fiber without an increase of the driving voltage, which includes a waveguide formed in one line, a signal electrode formed at an upped input side of the waveguide, to which signal electrode a signal voltage is applied as an upper electrode, and an absorption electrode formed at an upper portion of the waveguide for absorbing a higher order which are not easily absorbed by the signal electrode and for increasing a dissipation ratio.

Abstract: A multi-quantum-well Mach-Zehnder optical phase modulator selectively generates positive and negative frequency chirp. The modulator has an asymmetric input y-junction coupler and an asymmetric output y-junction coupler joined by interferometric arms defining two optical paths of unequal length so as to generate a fixed phase difference of .pi. or an integral odd multiple thereof. The modulator has electrodes on each arm for receiving modulating electric fields in a push-pull relationship. A control electrode is provided on one of the arms for receiving a control electric field. The modulator, when driven without any control electric field generates negative frequency chirp, and selectively generates positive frequency chirp in response to adjustment of the control electric field. As an alternative, the length differential between respective arms can be selected to generate a phase difference of .pi./2, in which case control electrodes are required on each of the interferometric arms.

Abstract: An optical fiber which modifies the optical signals propagated through the fiber and has refractive properties which change in response to electromagnetic energy. The outer surface of the fiber forms at least one groove extending along a selected length of the fiber for receiving an electrode, which would apply an electrical voltage to the fiber resulting in a change of the refractive properties of the fiber.

Abstract: When an electric signal outputted from a signal source (101) is converted to a light signal in an electrica-optical converting portion (104), a distortion component such as secondary or tertiary distortion is caused in the light signal to deteriorate transmission quality. Therefore, the light signal outputted from the electrica-optical converting portion (104) is further intensity-modulated with the same electric signal in an external light modulation portion (106) to forcibly cause a distortion which is out of phase with and of the same amplitude as the distortion component caused in the electrical-optical converting portion (104), thereby canceling the distortion component included in the light signal. Consequently, an optical transmission system capable of high-quality optical transmitting can be realized while employing a device having equivalent performance with the conventional devices.

Abstract: A method and system for the transmission of signals over a large capacity local access network which provides users a dedicated two-way link to a central office The network is built along a single optical fiber ring. Connection to the fiber is obtained by combining time and frequency division multiplexing techniques and by using an optical channel-dropping filter. Optical signals are generated at the central office. The users have a simple device integrated with the channel-dropping filter to receive and transmit data without the use of an optical source.

Abstract: After a shadow mask that is separate from a semiconductor substrate is used and is arranged over the semiconductor substrate via a wafer holder installed in a reaction chamber of a vapor-phase epitaxial system so that a predetermined space d can be secured, a semiconductor thin film crystal including a core layer and a cladding layer is grown by organometallic vapor-phase epitaxy. A core layer wherein the thickness of a grown film in an area which is opposite to a masking part of the shadow mask on the semiconductor substrate is reduced in the tapered shape can be readily obtained by introducing this process for growth in a normal process for fabricating a semiconductor guided-wave optical device. A semiconductor guided-wave optical device and a method of fabricating thereof wherein the thickness of a film which is to be a waveguide is tapered and the width of the waveguide is tapered without deteriorating crystallinity by a new crystal growing method using this shadow mask are obtained.

Abstract: The device comprises a layer of silicon separated from a substrate by a layer of insulating material. A rib having an upper surface and two side surfaces is formed in the layer of silicon to provide a waveguide for the transmission of optical signals. A lateral doped junction is formed between the side surfaces of the rib such that an electrical signal can be applied across the junction to control the density of charge carriers across a substantial part of the cross-sectional area of the rib thereby actively altering the effective refractive index of the waveguide.

Abstract: An electro-optic optical modulating apparatus comprises an optical waveguide, which has electro-optic effects, and at least a single pair of electrodes, which are located in the vicinity of the optical waveguide. A driving circuit applies a radio-frequency voltage across the electrodes. A modulating circuit modulates the amplitude of the radio-frequency voltage in accordance with a predetermined signal. The amount of a modulated optical wave is thus prevented from fluctuating due to a DC drift phenomenon.

Abstract: A passive region is provided on one side or both sides of a waveguide-type optical modulator. Thereby, it is possible to obtain a high-speed optical modulator package superior in mechanical strength, thermal characteristic, high-frequency characteristic, and extinction characteristic. Moreover, it is possible to increase the operating speed of an optical fiber transmission equipment by applying the optical modulator package to the optical fiber transmission equipment.

Abstract: A new class of energy interaction devices, particularly optical energy transfer devices and energy guiding devices, use an energy field, particularly an electric field, applied to a poled structure to control energy propagation in a solid material. The poled structures, which may form gratings in thin film or bulk configurations, may be combined with waveguide structures to guide energy beams such as optical or acoustic beams. Electric fields applied to the poled structures, such as electrically-activated gratings, control routing of optical energy. Optical devices include but are not limited to, frequency-selective switchable- and adjustably-tunable reflectors, splitters, directional couplers, frequency-tunable switches and efficient beam combiners, as well as polarized beam combiners, am and fm modulators, mode selectors, energy transfer devices, optical data readers, panel display devices, and waveguide/reflector switching arrays.

Abstract: An optical device for modulating or interacting with radiation guided and propagating along an optical longitudinal axis of an optical waveguide, such as, an optical fiber, has a different directional geometry compared to conventionally comparable devices such as, for example, plasmon or planar surface modulators for optical fibers. The geometry includes a nonlinear, electro-optic medium formed between two spatially disposed electrodes. The medium/electrode sandwich is aligned along the waveguide longitudinal propagating axis and extends in a radial direction from the optical waveguide core with the inner end of the medium in spatial proximity to the waveguide core for evanescent coupling with the radiation field propagating in the waveguide.

Abstract: An optical device includes a semiconductor optical modulator element (46) which is connected to an end of a signal line (42) in form of a microstrip high-frequency line and whose other electrode is connected to a ground electrode (48) by a bonding wire (50). The signal line (42) includes first and second line portions (42a, 42b). The first line portion (42a) nearer to the entrance of a high-frequency signal has a width W1 determined to adjust its characteristic impedance to 50.OMEGA. and a length L1 equal to an integer multiple of 1/4 of its own guide wavelength. The second line portion (42b) has a width W2 determined to adjust its impedance to an intermediate value between the impedance of the optical modulator element 46 and the impedance of the first line portion (42a), and a length L2 equal to an integer multiple of 1/4 of its own guide wavelength.

Abstract: An optical switch includes a substrate, an optical waveguide, arm waveguides, S-shaped curved waveguides, and two pairs of control electrodes. The substrate has an electro-optic effect. The optical waveguide is formed on the substrate and on which light is incident. The arm waveguides are formed on the substrate and branched from the light-incident optical waveguide into a Y shape. The S-shaped curved waveguides are formed on the substrate and continuous to the arm waveguides to form S-shaped curves. The first pair of control electrodes are formed on the arm waveguides and S-shaped curved waveguides. The second pair of control electrodes are formed on the substrate to be close to the first pair of control electrodes at predetermined gaps thereto.

Abstract: On a surface of an n-InP substrate, a mask of SiO.sub.2 layer wide in an active region and narrow in a passive region and having a constant gap width. In a waveguide region defined between the masks, a waveguide structure constituted of an n-InGaAsP guide layer, an undoped InGaAsP optical waveguide layer and a p-InP clad layer is selectively grown to form. Again, utilizing SiO.sub.2 layer, a mask is formed on the surface of the p-InP layer in the active region and a pair of masks defining the waveguide structure is formed in a the passive region, and high resistance InP layer is grown. Also, in the active region, a p-InP layer, a p-InGaAs contact layer are selectively grown. By forming SiO.sub.2, a window is formed to form p-side electrode. An n-type electrode is formed on the back surface of the substrate, By this, a device having an optical loss in the active region and passive region becomes low, a coupling coefficient between both regions is high.

Abstract: An optic modulator implemented on a substrate that is conductive to light and which includes a pair of light waveguides formed on the substrate is described. The waveguides extend substantially coextensively with one another and are separated from one another by a transverse distance that gradually varies along the courses of the waveguides. The waveguides are arranged to pass between an outer electrode assembly and a center electrode assembly. The outer electrode assembly substantially surrounds the center electrode assembly in such a manner as to create an electric field between the center electrode assembly and the outer electrode assembly when a voltage is applied across the outer and center electrode assemblies.

Abstract: Disclosed is an optical control device which has a LiNbO3 or LiTaO3 crystalline substrate having electrooptic effect; a channel-type optical waveguide which is formed in the crystalline substrate by doping metal; an optically transparent film layer formed on the crystalline substrate; and electrodes formed on the optically transparent film layer; wherein the crystalline substrate has a surface except a region which waveguided-light through the channel-type optical waveguide propagates or an entire surface under which a layer doped by metal is formed.

Abstract: This invention aims at providing an optical waveguide device capable of stably operating for an extended period of time. The optical waveguide device comprises an optical waveguide path formed inside a surface of an electro-optical substrate, a buffer layer formed on the optical waveguide path, and a driving electrode for impressing an electric field so as to change a refractive index of the optical waveguide path, wherein the buffer layer is made of a transparent dielectric or insulator of a mixture between silicon dioxide and an oxide of at least one element selected from the group consisting of the metal elements of the Groups III to VIII, Ib and IIb of the Periodic Table and semiconductor elements other than silicon, or a transparent dielectric or insulator of an oxide between silicon and at least one of the metal elements and semiconductor elements described above.

Abstract: A flat panel display is based on a new switching technology for routing laser light among a set of optical waveguides and coupling that light toward the viewer. The switching technology is based on poled electro-optical structures. The display technology is versatile enough to cover application areas spanning the range from miniature high resolution computer displays to large screen displays for high definition television formats. The invention combines the high brightness and power efficiency inherent in visible semiconductor diode laser sources with a new waveguide electro-optical switching technology to form a dense two-dimensional addressable array of high brightness light emissive pixels.

Abstract: An acousto-optical filter (AOTF) having reduced sidelobes. The AOTF is fabricated with a waveguide formed on a substrate along an optical axis. An incoming beam of light is coupled into the waveguide. An acoustic wave beam is induced by an interdigitated transducer. The acoustic wave beam follows an acoustic wave beam axis which crosses the optical axis. The transducer is driven by an externally-generated electric signal. The frequency of the acoustic wave beam is determined by the frequency of the electric signal. The acoustic wave beam induces a diffraction grating in the waveguide as the acoustic wave beam crosses the optical axis, and this in turn diffracts the beam of light. The grating couples the transverse electric and transverse magnetic polarization modes of the light, but only within a narrow band of optical wavelengths. The cross-section of the intensity of the acoustic wave beam can be tapered to further reduce the sidelobes of the passband defined by the frequency of surface acoustic wave beam.

Abstract: Even when manufacturing of a waveguide is fluctuated and an optical parameter is fluctuated or a wavelength of emitted light is fluctuated, a phase difference between two intrinsic modes can be compensated (positive integral multiple of .pi.). Thus, it is possible to prevent a reproduced signal from being deteriorated by elliptically polarized light. A magneto-optical reproducing pickup includes an optical waveguide (4) for guiding light reflected on a magneto-optical recording medium to a differential photo-detecting unit (9) side and phase compensating circuitry for compensating a phase difference between light components of a TE mode an a TM mode included in reflected light.

Abstract: An integrated tunable optical filter comprising a substrate made of a semiconducting material. The substrate includes first and second sections. The first section forms a tunable transmission filter, based on a codirectional coupler having a low selectivity. The second section forms a reflection filter with a reflection spectrum containing a number of peaks. A first injector, designed for current injection into said first section, is provided. Thus, the filter response of the first section is shifted in wavelength over a large wavelength range. There is also a second injector, designed for current injection into the second section. As a result, the reflective spectrum of the second section is slightly shifted in wavelength, in such a way that one reflection peak of the reflection spectrum corresponds to the coupling wavelength of the first section. Consequently, the total filter response has a very narrow bandwidth and wide tunability.

Abstract: A digital optical switch and a method for digital optical modulation are disclosed. The digital optical switch is comprised of an optical waveguide having an input control region, a connection region, and a separation region, and a generator which generates a smoothly varying electric field in an input control region of said optical waveguide and a substantially constant electric field in said separation region of said optical waveguide. The optical waveguide may be either an x-shaped optical waveguide or a y-shaped optical waveguide.

Abstract: A new class of optical energy transfer devices and energy guiding devices uses an electric field to control energy propagation using a class of poled structures in solid material. The poled structures, which may form gratings in thin film or bulk configurations, may be combined with waveguide structures. Electric fields applied to the poled structures control routing of optical energy. Devices include splitters, parallel and Y couplers, mode converters and energy leakage attenuators.

Abstract: The present application relates to a waveguide-type optical device comprising an impedance matching means for matching impedance of a side of a control signal source supplying a control signal to control propagation of light waves in an optical waveguide of the waveguide-type optical device and impedance of a side of a signal electrode receiving the control signal, wherein this impedance matching means is provided between the side of the control signal source and the side of the signal electrode. A waveguide-type optical device of the present invention overcomes characteristic deterioration caused by un-matching of impedance. Additionally, the present invention can extend the degree of freedom for designing a waveguide-type optical device.

Abstract: A waveguide type electro-optical element is made up of a proton-exchanged optical waveguide formed on a substrate which possesses an electro-optical effect. At least one pair of electrodes is formed on the substrate adjacent to the optical waveguide with a buffer layer being disposed between the substrate and the electrodes. A guide beam propagating through the waveguide is diffracted as a result of the application of a voltage to the electrodes. The buffer layer is made of material which has a specific resistance ranging between 10.sup.7 -10.sup.11 .OMEGA.cm. The optical waveguide may be of a form having a split-type optical waveguide consisting of the combination of two Y-shaped waveguides, and a pair of channel optical waveguides constituting a directional coupler.

Abstract: At least one waveguide 2,3,4 are formed on a crystal substrate 1 having an electro-optical effect. A buffer layer 5 (with a dielectric constant of 1.1 to 40) is formed on the waveguide. Lower CPW electrode structures 6,7 are formed on the buffer layer. Intermediate electrode structures 8,9 are formed thereon and additional electrode structure 10 is formed on the intermediate signal electrode 8.

Abstract: An optical processing device for light radiation provides non-linear transfer functions in an optical guide. A coupled quantum well modulator is reverse biased by an adjustable dc voltage source through an impedance and light radiation to be processed is sent in parallel with the layers composing the modulator guiding zone. The coupled quantum well modulator has a multiplicity of layers including some which form a guide zone comprised of a sequence of alternating quantum wells and barrier layers. The light radiation to be processed passes parallel to the layers through this guiding zone.

Abstract: A high speed optical switching device includes a waveguide arrangement, incorporating a pn junction, with a large bondpad for the purposes of increasing the capacitance presented by the device. Data and control signals can be input at an input port of the waveguide arrangement, presence of the control signal operating to modify the optical path length of the device for the data signal. By incorporating the device in an interferometer arrangement, or by exploiting a Fabry-Perot cavity of the device, it can be used to transmit the data signal selectively, for instance so as to demultiplex a time multiplexed optical communications signal. The high capacitance provides a very short recovery times so that data rates of 10 GHz and substantially above can be accommodated.

Abstract: Velocity-matched electrodes that are sufficiently index-matched to use in linearized directional-coupler modulators are provided by placing a low dielectric constant material layer over the travelling-wave modulator electrodes, followed by a metal layer that is electrically connected to a ground electrode. The low dielectric constant layer between the grounded metal layer and the active electrode lowers the effective RF dielectric constant, which lowers the RF index of refraction. The RF index of refraction is matched to the optical index of refraction by controlling the thickness of the low dielectric constant layer, which is deposited with standard RF sputtering techniques that allow for precise control over the layer thickness. As a result, more precise velocity matching and greater reproducibility than with prior velocity matching techniques is achieved.

Abstract: A modulating optical element having ports wherein either port can output or receive light signals. An electrooptic effect is applied to the optical element to allow the light signals to pass or not pass through the optical element. Due to the electrooptic effect in preventing signals from passing through the optic element, light signals radiate out of the optical element and are absorbed by the substrate of the optical element assembly. Rather than being lost, the energy from the light signal is converted to current which may be used for other purposes in the modulator system, such as bias stabilization.

Abstract: A Mach-Zehnder optical modulator in which the chirp parameter can be varied by adjusting the optical power splitting ratio between the two arms of the interferometer. The modulating voltage is supplied to a single arm or alternatively to both arms in a push-pull configuration. For an appropriate power splitting ratio negative chirp is achieved with approximately equal push-pull modulating drive voltage. This results in optimum distance and bit rate characteristics with low drive power.

Abstract: A TE-TM mode converter of a polymer electro-optic polarization waveguide type uses the electro-optic birefringence and the electro-optic effect as a non-linear optical waveguide medium, in which an optical director formed during the poling of a polymer thin film is determined by the direction of the poling electrical field. The poling electrode design enables the optical director having the angle of 45.degree. to the electrical direction of the TE and TM modes to be formed in the polymer thin film. When the waveguide receives the incident light of the TE mode or TM mode, the TE (or TM) mode is switched into the TM (or TE) mode by an effective refraction factor between the optical director and the director perpendicular thereto. If a length of the poling electrode and the birefringence of the waveguide is adjusted, the changes of various electo-optic polarization states are possible. The poled thin film has an electro-optic effect.

Abstract: A waveguide type optical device is provided. Waveguides of titanium metal formed in a crystal substrate of LiNbO.sub.3 having an electro-optic effect. A buffer layer of a dielectric material is formed on the crystal substrate and coplanar waveguide electrodes of a signal electrode and two ground electrodes are formed on the buffer layer. A substrate of a low dielectric constant material formed on the back surface of the crystal substrate and having a slit or concave formed on portions other than end portions of the side to be opposed to the back surface.

Abstract: A wavelength conversion element includes a substrate made of LiTaO.sub.3 of non-linear medium, a three-dimensional waveguide formed in the substrate and a second harmonic generation portion for defining a change in refractive index in the waveguide with a period .LAMBDA. and generating a second harmonic of a fundamental wave introduced into the wave guide, where .LAMBDA.=2 m.pi./{.beta.(2.omega.)-2.beta.(.omega.)}, m is a natural number, .omega. is a frequency of fundamental harmonic, .beta.(.omega.) is a propagation constant of the fundamental wave, and .beta.(2.omega.) is a propagation constant of second harmonic.

Abstract: A tunable optical filter for use in wavelength division multiplexing systems. The optical filter contains a plurality of tunable reflection gratings which block all of the channels in the incoming lightwave. An electrode or a heating element is provided for each reflection grating to tune the reflection gratings so that their reflection bands do not coincide with a desired channel or channels thereby allowing the desired channel or channels to pass through the filter.

Abstract: A light control device including an electro-optical material, a light refraction device mounted on the surface of the electro-optical material and electrodes provided on respective front and back major surfaces of the electro-optical material. A waveguide layer may be formed on the electro-optical material, with one electrode formed on an upper major surface of the waveguide layer and another electrode on the lower major surface of the electro-optical material. A prism or a diffraction grating may be used as the light refraction device. The light control device is particularly useful in laser printers and optical disk devices.

Abstract: An electrically controllable filter device is provided which comprises an electrode structure which induces a filter for waves within a given wavelength range. The electrode structure is so formed that it within the given wavelength range acts as a filter merely upon electrical feeding whereas it in the absence of electrical feeding has no filtering effect. Furthermore, the electrode structure is so arranged that the filter depending on how the electrode structure is fed can be tuned to a number of different discrete frequencies.

Abstract: A broadband, electrooptic modulator is disclosed which, in a first embodiment, comprises: a substrate having substrate modes, having electrooptic effects, and having a first optical waveguide adapted to receive and transmit light therethrough in a first direction and with a first phase velocity; a buffer layer disposed on the substrate; and a coplanar waveguide electrode structure having a coplanar mode and being disposed on the buffer layer for receiving an electrical signal propagating therethrough in the first direction with a second phase velocity to phase modulate the light in the optical waveguide at a frequency in the range from 0 Hz up to substantially 40 GHz.

Abstract: An elegant design for an optical modulator having a high Q is described. The modulator is made up of a straight-forward microwave guide within which a block of a monocrystalline electro-optic material such as lithium niobate is positioned. The modulator is dimensioned to support sequentially standing waves of modulating energy within the desired bandwidth. Optical radiation to be modulated is introduced into the crystal. In one embodiment designed particularly for the 2-15 GHz range, the amount of crystalline material necessary to interact with the incoming radiation is selected to be a minimum, and in another embodiment designed for the 15-75 GHz frequency range, a zig-zag reflection pattern is provided within the crystal.